EP2088183A1 - Fire retardant compound for production of a intumescent fire retardant item - Google Patents

Abstract

Fire protection mixture (I) to prepare an intumescent fire protection article or intumescent fire protective article (II), comprises a matrix material, in which an intumescent expandable graphite (a); an intumescent, alkane filled microcapsule (b) or one or more encapsulated nitrogen-eliminated and/or carbon dioxide eliminated propellants (c); one or more flame protective agents (d), phosphate-, halogen-, mineral-, nitrogen-, boron- containing fire protective agent, and silicate layer on the basis of aluminum silicate-clay-mineral; and optionally other components (e), are embedded.

Description

The present invention relates to (a) a fire-protection mixture for producing an intumescent fire protection article and (b) an intumescent fire protection article, each comprising a matrix material, in which the constituents (i) intumescent expandable graphite, (ii) (A) intumescent, alkane-filled microcapsules or (ii) (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants, (iii) one or more selected flame retardants, and optionally (iv) other ingredients are embedded. For further features of a fire-resistant mixture according to the invention or an intumescent fire protection article according to the invention, see below.

In particular, the invention relates to an intumescent fire protection article according to the invention, which is a pipe bulkhead for combustible pipes or a component of such a pipe bulkhead, or a Kabelabschottung or a component of such Kabelabschottung.

Another aspect of the present invention relates to the use of a fire-protection mixture according to the invention for producing a (preferably according to the invention) intumescent fire protection article.

Furthermore, the present invention relates to a corresponding method for producing a fire-resistant mixture according to the invention for producing a (preferably according to the invention) intumescent fire protection article, as well as a method for sealing flammable pipes or cables.

Breakthroughs, bushings (eg for cable strands or pipes) and other openings in walls, floors and / or ceilings of buildings must be provided with fire protection seals for the purpose of fire protection, to prevent fire and smoke from passing through in case of fire Openings in other parts of the building can spread. Usually, these fire-resistant seals contain foaming materials or consist of such and can be used in the form of curing, informal fire protection compounds or in the form of prefabricated strips, plates, bricks and the like, which are introduced into the openings to be sealed or this in the form of a cover in front of the masonry.

Foaming materials used for such fire protection seals usually contain one or more expandable graphite intercalation compounds as intumescent fire protection additive, which are also known as intumescent expandable graphite and are commercially available. The term intumescent is a designation from the fire protection and designates a mode of action of special materials, which foam in case of fire, i. are thermally expandable, and form a complete or at least partially insulating protective layer (e.g., in the form of a rigid foam).

Expandable graphite intercalation compounds are compounds in which small foreign molecules were intercalated between the lattice layers of graphite. Such compounds are usually prepared by dispersing purified natural graphite in a solution containing Contains oxidizing agent and a strong acid. Due to the oxidation that takes place in the layer lattices water-insoluble salts and volatile constituents, which are then responsible for the expansion in case of fire. Descriptions of corresponding manufacturing processes can be found, for example, in EP 00 85 121 and US 4,091,083 ,

By choosing the acid used and the oxidizing agent used, the later properties of the expandable graphites can be partially adjusted:

For example, the use of sulfuric acid produces intumescent expanded graphites with a thermally induced start of expansion at about 200.degree. The temperature at which the thermally induced expansion begins is referred to as the onset temperature (in the context of the present text). The use of nitric acid or acetic acid, however, leads to an onset temperature of intumescent expanded graphite in the range of about 150 to 160 ° C. In this case, the use of acetic acid is preferable to the use of nitric acid, as in expanded graphite containing nitric acid, nitrous gases or nitrogen oxides can be formed in case of fire.

The oxidants used mainly affect the expansion volume, the expansion pressure and the amount of expansion at certain temperatures. In the past, potassium dichromate was used as a particularly strong oxidizing agent. However, as this compound is highly carcinogenic, it is no longer used in, for example, Europe and North America. The use of potassium chromate as an oxidizing agent is no longer common. Hydrogen peroxide and potassium permanganate are safer from an environmental and safety point of view and are therefore preferably used as the oxidizing agent.

As soon as a corresponding expandable graphite is heated to a temperature equal to or above the onset temperature, the expandable graphite spreads to a volume in the range of less than 10 times to more than 400 times the original volume. The expansion is caused by the fact that the intercalates embedded in the layer grid structure of the graphite are decomposed by this heating to form gaseous substances, whereby the graphite particles are expanded perpendicular to the layer plane (cf. EP 00 85 121 ).

This volume increase is made use of in intumescent masses, which are used, for example, for fire protection of pipe penetrations through walls and ceilings of buildings. In case of fire, then reaching the onset temperature leads to an expansion of the graphite particles contained and thus the entire intumescent mass sealing the implementation. As a result, a breakthrough of the fire can be prevented or at least delayed by this implementation even after the burning of the guided through the pipes.

There are already a number of attempts to use such expanded graphite as intumescent fire protection additives in fire protection seals.

In order to seal, for example, an annular gap fire protection, appropriate fire protection seals can be introduced around the pipe passed through the wall in the opening or mounted in the form of a cover on the wall. The problem is, however, that occurs in the case of introducing a fire protection seal as a pipe bulkhead in the remaining annular gap of the heat input in case of fire over a relatively small surface. Since the desired expansion of the intumescent fire protection additive in the fire protection compound depends on this heat input, according to our own investigations, this can result in the tube to be sealed collapsing before the onset temperature of the intumescent fire protection compound is reached. In this case, a penetration of the fire and the smoke through the opening is possible.

• als wichtigste Kenngröße die Onset-Temperatur des intumeszierenden Materials, d.h. für einen Blähgraphit die Temperatur, bei der die thermisch bedingte Expansion der Graphitpartikel des Blähgraphits beginnt;
• die Expansionsgeschwindigkeit des intumeszierenden Materials im Bereich der Onset-Temperatur [% / °C], welche die Ausdehnung des Materials in Prozent pro Grad Temperaturerhöhung angibt;
• das maximal erzielbare Expansionsvolumen [%/mg], welches die Ausdehnung des Materials (%) normiert auf die eingewogene Materialmenge (mg^-1) angibt;
• die Temperatur, bei der 100 % des maximal erzielbaren Expansionsvolumens erreicht werden (T₁₀₀),
• der mittlere Ausdehnungskoeffizient α [K^-1] zwischen der Onset-Temperatur und der T₁₀₀, definiert als α = L₀ ^-1 · ΔL · ΔT^-1, worin ΔL für die durch die Temperaturänderung ΔT hervorgerufene Längenänderung und L₀ für die Ausgangslänge einer Probe des intumeszierenden Materials steht. Die Längenänderung der Probe ist ein zur Ausdehnung des intumeszierenden Materials äquivalenter Messparameter und wird gemäß thermomechanischer Analyse (TMA) bestimmt (vgl. hierzu EP 1 489 136 A1 ).

This is the case in particular with conventional intumescent fire protection seals, which expandable graphites as intumescent Contain fire protection additive, since their expansion behavior just are not able to satisfy for this application. Characteristic parameters for the expansion behavior of intumescent materials, in particular an expanded graphite, are, for example:

• the most important parameter is the onset temperature of the intumescent material, ie for an expanded graphite the temperature at which the thermally induced expansion of the graphite particles of the expandable graphite begins;
• the rate of expansion of the intumescent material in the range of the onset temperature [% / ° C], which indicates the expansion of the material in percent per degree of temperature increase;
• the maximum achievable expansion volume [% / mg], which indicates the expansion of the material (%) normalized to the weighed amount of material (mg ^-1 );
• the temperature at which 100% of the maximum achievable expansion volume is reached (T ₁₀₀ ),
• the mean expansion coefficient α [K ^-1 ] between the onset temperature and the T ₁₀₀ , defined as α = L ₀ ^-1 · ΔL · ΔT ^-1 , where ΔL for the change in length caused by the temperature change ΔT and L ₀ for the output length a sample of the intumescent material is. The change in length of the sample is an equivalent measurement parameter for the expansion of the intumescent material and is determined according to thermomechanical analysis (TMA) (cf. EP 1 489 136 A1 ).

The parameters mentioned, in particular the rate of expansion in the area of the onset temperature [% / ° C], the maximum achievable expansion volume [% / mg], the T ₁₀₀ and the mean expansion coefficient α are derived, for example, from the thermomechanical analysis method from (see for example EP 1 489 136 A1 ). Another characteristic parameter for describing the expansion behavior of intumescent materials, in particular an expanded graphite, is the maximum free expansion. The maximum free expansion [ml / g] describes the volume increase of the thermally expanding material or of an intumescent expanded graphite, based on the amount of material used in grams.

According to the prior art, predominantly commercially available graphite particles (expandable graphites) are used as intumescent fire protection additives in corresponding intumescent fire protection seals which, as already described above, contain sulfuric acid, nitric acid or acetic acid and thus have an onset temperature of about 200.degree in the range of 150 to 160 ° C. In view of the achievable expansion volume and the rate of expansion in the range of the onset temperature, however, these expandable graphites are unable to satisfy.

It has been found in our own investigations that when using such conventional expandable graphite and when introducing the appropriate fire seal in the interior of the openings to be closed, the expansion parameters of this Blähgrahite not sufficient to at a (as described above) correspondingly low heat input, the intumescence of Fire protection seal or the corresponding mixture quickly enough to trigger and to achieve a sufficiently large expansion volume to ensure the fire seal even when collapsing a guided through the opening pipe (see EP 1 489 136 A1 ).

In EP 1 489 136 A1 Fire protection investigations are published which show that the expandable graphite used as an intumescent fire protection additive (with a particle size of 250 to 400 μm) for use in corresponding fire protection seals should preferably have the following expansion parameters in order to ensure an efficient pipe seal: Onset temperature [° C]: ≤ 160 Volume with regard to weight, ie maximum achievable expansion volume [% / mg]: ≥ 550 Expansion rate in the range of the onset temperature [% / ° C]: ≥ 20 Mean expansion coefficient α between onset temperature and T ₁₀₀ [1 / K]: ≥ 0.1

The measurement of these expansion properties is carried out according to EP 1 489 136 A1 with the help of thermomechanical analysis.

In EP 1 489 136 A1 it is also described that an appropriate adjustment of these preferred expansion parameters on the particle size of the graphite particles is unsuitable. Although larger graphite particles have a correspondingly higher expansion volume, the problem arises in the manufacture of the intumescent fire protection seal that the larger particles are more easily damaged and degraded by the shearing forces when introducing the fire protection additives into the polymer matrices by mixing processes compared to smaller graphite particles can be.

The consequences are usually a breakage of the graphite particles with concomitant corrosion of machinery and tools by the acid released from the expandable graphite particles, an undesired reaction of the released acid with other formulation constituents and a deterioration in the expansion behavior.

In EP 1 489 136 A1 An approach to solve these problems is described. This should reduce the onset temperature of the graphite intercalation compounds and increase the expansion volume and rate of expansion in the onset temperature range.

This can be achieved by incorporating or adding, in addition to the corresponding acid, metal halides and a nitroalkane of the general formula CH ₃ (CH ₂ ) _n NO ₂ , preferably nitromethane, in the production of expandable graphite.

However, there are problems associated with this approach. Modification of the expandable graphite by metal halides is environmentally unsuitable for production because, in the production of such modified graphite using metal halides, more than twice the amount of heavy metal halides would be required per ton of natural graphite. The use of nitroalkanes of the general formula CH ₃ (CH ₂ ) _n NO ₂ is disadvantageous because of its oxidizing properties for a modification of expandable graphites which are to be used in corresponding fire protection seals.

It was therefore the primary object of the present invention to provide a fire-resistant mixture for producing an intumescent fire protection article and corresponding intumescent fire protection articles with which it succeeds in case of fire, even at lower temperatures and / or in unfavorable conditions of heat transfer to the fire protection mixture or To improve the intumescent fire protection article, the sealing or closure of an opening in walls, floors and / or ceilings of buildings without the addition of metal halides significantly.

Preferably, a fire protection mixture or corresponding intumescent fire protection articles are to be specified, which are particularly well suited for sealing passages for pipes and / or cables (strands). Preferably, larger openings, for example for thicker-walled pipes with a large pipe cross-section, should be securely sealed by the present invention.

Furthermore, with the present invention, the use of a fire-resistant mixture according to the invention for producing a (preferably inventive) intumescent fire protection article and a corresponding method for producing such a fire-resistant mixture according to the invention should be specified.

In addition, a method should be specified for the partitioning of combustible pipes or cables.

Other objects underlying the present invention will become apparent from the following and the appended claims.

According to EP 1 489 136 A1 and DE 101 62 532 C1 an improvement in the expansion behavior is sought solely to achieve an optimization of the expansion parameters of the expanded graphite used. In contrast, the present invention is based on the approach that all parameters of the overall system, ie the entire fire protection mixture or the entire intumescent fire protection article, are relevant for the desired fire protection application.

1. (a) Brandschutzmischung zur Herstellung eines intumeszierenden Brandschutzartikels, umfassend
   oder einen
2. (b) intumeszierenden Brandschutzartikel, umfassend
   ein Matrixmaterial, in das die folgenden Bestandteile eingebettet sind:
   1. (i) intumeszierender Blähgraphit,
   2. (ii) (A) intumeszierende, alkangefüllte Mikrokapseln, oder
      • (B) ein oder mehrere verkapselte Stickstoff-abspaltende und/oder Kohlendioxid-abspaltende Treibmittel (z.B. Porofor®, Kenitron® und Ficel® der Firma Lanxess; Azodicarbonsäurediamid als Stickstoff-abspaltendes Treibmittel, etc.)
   3. (iii) ein oder mehrere Flammschutzmittel ausgewählt aus der Gruppe bestehend aus: phosphathaltige Flammschutzmittel, halogenhaltige Flammschutzmittel, mineralische Flammschutzmittel, stickstoffhaltige Flammschutzmittel, borhaltige Flammschutzmittel und Schichtsilikate auf Basis von Aluminiumsilikat-Tonmineralien; und
      gegebenenfalls
   4. (iv) sonstige Bestandteile.

Accordingly, the present invention relates to a primary aspect of a

1. (A) fire protection mixture for producing an intumescent fire protection article, comprising
   or one
2. (b) intumescent fire protection article comprising
   a matrix material in which the following components are embedded:
   1. (i) intumescent expanded graphite,
   2. (ii) (A) intumescent, alkane-filled microcapsules, or
      • (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants (eg Porofor®, Kenitron® and Ficel® from Lanxess, azodicarboxylic acid diamide as nitrogen-releasing propellant, etc.)
   3. (Iii) one or more flame retardants selected from the group consisting of: phosphate-containing flame retardants, halogen-containing flame retardants, mineral flame retardants, nitrogen-containing flame retardants, boron-containing flame retardants and phyllosilicates based on aluminum silicate clay minerals; and
      possibly
   4. (iv) other ingredients.

According to a preferred embodiment, the present invention relates to a (a) fire protection mixture for producing an intumescent fire protection article (as described above) or a (b) intumescent fire protection article (as described above), wherein component (ii) consists of intumescent, alkane-filled microcapsules.

The present invention is based on an optimization of the expansion parameters of the overall system, preferably by the combination of at least two different intumescent additives, in particular (i) intumescent expandable graphite and (ii) (A) intumescent, alkane-filled microcapsules or (ii) (B) or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants is achieved.

It was particularly surprising that by such a combination, in particular by a combination of (i) expandable graphite and (ii) (A) intumescent, alkane-filled microcapsules (as additional propellant), the expansion parameters of the fire protection mixture or the Fire protection article can be improved so that it succeeds in the event of fire, even at lower temperatures and unfavorable conditions of heat transfer to the fire protection mixture or the intumescent fire protection article openings in walls, floors and / or ceilings, especially larger openings, eg. B. for thicker-walled pipes with a large pipe cross-section, secure seal.

According to the present invention, a fire protection mixture according to the invention or an intumescent fire protection article according to the invention comprises a matrix material in which the described components are embedded. A matrix material in the context of the present text is a material in which other constituents are embedded, i. a material which encloses or comprises the components (to be used according to the invention). Preferably, the matrix material is based on a polymer or a polymerizable material. The matrix material is preferably based on a polymer and contains as polymer at least one member of the natural and synthetic rubbers, polyurethanes, polyvinyl acetates, polyvinyl ethers, polyvinyl propionates, polystyrenes, silicones and / or polymethacrylates.

According to a preferred embodiment, the matrix material is a polymer matrix consisting of a one-component system (eg based on moisture-curing PU prepolymer) or a two-component casting system (eg in the prepolymer process or in the so-called one-shot Method produced).

According to a preferred embodiment, the matrix material is a polymer matrix consisting of a two-component casting system based on polyurethane, produced in the so-called one-shot process. The first component for the construction of the polyurethane matrix in this case consists of a polyol mixture which preferably contains, in addition to one or more polyols, at least one short-chain crosslinker and / or chain extender based on alcohol. Furthermore, this first component usually contains the constituents to be used according to the invention (i) intumescent expandable graphite, (ii) (A) intumescent, alkane-filled microcapsules or (ii) (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants, one or more flame retardants described above as component (iii) and optionally (iv) other ingredients such as catalysts, pigments and / or other additives (eg anti-aging agents, antioxidants, stabilizers, etc.). The second component for the construction of the polyurethane matrix is based on di- or polyisocyanates. By mixing the second component with the first component, a reaction occurs in which the reaction mixture hardens to form a polyurethane system.

The one or more polyols of the first component are preferably selected from polyols of the group polyesters, polyethers, polycarbonates and / or polycaprolactones. Depending on the chain length and the number of branches in the polyol, mechanical properties can be influenced.

Preferably, the at least one polyol has a molecular weight in the range of 500 to 6000 g / mol, with a molecular weight in the range of 1000 to 3000 g / mol being particularly preferred.

Furthermore, the at least one polyol preferably has an OH functionality in the range from 2 to 3, although higher functionalities can also be used.

The at least one short-chain, preferably bi- or polyfunctional, alcoholic chain extender or crosslinker is preferably selected from the group of 1,4-butanediol (bifunctional, M = 90.1 g / mol), 1,6-hexanediol (bifunctional, M = 118.2 g / mol), ethylene glycol (bifunctional, M = 62.1 g / mol), propanediol (bifunctional, M = 76.1 g / mol), glycerol (trifunctional, M = 92.1 g / mol) , Di-trimethylolpropane (Di-TMP, tetrafunctional, M = 250.3 g / mol), trimethylolpropane (TMP, trifunctional, M = 134.2 g / mol) and / or cyclohexanedimethanol (bifunctional, M = 144.2 g / mol). As special Advantageously, a mixture of crosslinkers has been found, which based on the total weight of the crosslinker mixture 30 to 90 wt .-% bifunctional chain extenders, preferably 1,4-butanediol, and 10 to 70 wt .-% trifunctional crosslinker, preferably trimethylolpropane comprises.

The second component, which is based on di- or polyisocyanates, comprises at least one di- or polyisocyanate, preferably selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI, bifunctional, M = 250.3 g / mol) and its isomers , 3,3'-dimethyldiphenyl diisocyanate (TODI, bifunctional, M = 264.3 g / mol), tolylene diisocyanate (TDI, bifunctional, M = 174.2 g / mol), naphthalene-1,5-diisocyanate (NDI, bifunctional, M = 210.2 g / mol), hexamethylene diisocyanate (HDI, bifunctional, M = 168.2 g / mol), trifunctional condensates of hexamethylene diisocyanate of the biuret or trimer type (isocyanurate), isophorone diisocyanate (IPDI, bifunctional, M = 208.3 g / mol) and / or 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ -MDI, bifunctional, M = 262.4 g / mol), wherein a mixture of isomers of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in an isomeric ratio from 50:50 to 80:20 is particularly preferred. For example, isocyanates of the Suprasec series from Huntsman or Desmodur VP PU 0129 from Bayer have proven to be particularly suitable in their own experiments.

In the context of the present invention, both a component of the two-component casting system described according to a preferred embodiment of the present invention, which contains the constituents (i), (ii), (iii) and optionally (iv), as well as a mixture first and second component of the two-component casting system in each case a fire protection mixture according to the invention.

For the purposes of the present invention, it is particularly advantageous for a fire protection mixture according to the invention or a fire protection article according to the invention to have a low water content, preferably a water content of not more than 0.1% by weight, based on the total weight of the Fire protection mixture according to the invention or the fire protection article has. Optionally existing residual moisture, such as from a polyol mixture of the first component according to a preferred embodiment of a matrix material or intumescent expandable graphite to be used according to the invention, for example, with a di- or polyisocyanate of the second component react to release carbon dioxide, resulting in a puffing the mixture during the manufacturing process. Therefore, a fire-retardant mixture according to the invention for the manufacture of an intumescent fire protection article is preferably a water adsorber as Baylith T ^® added. As a result, swelling of the mixture during the manufacturing process can be reduced or prevented. Baylith ^® T is a molecular sieve on Na-A zeolite base having a pore size of about 4 Angstroms. This is commercially available, for example, as UOP T powder (eg Obermeier). Accordingly, a water adsorber in a further preferred embodiment of a (a) fire-protection mixture according to the invention or a (b) intumescent fire-protection article according to the invention represents an (iv) other constituent of the matrix material included.

Particularly suitable is a preferred embodiment of a (a) fire protection mixture according to the invention or a (b) fire protection article according to the invention, wherein the (i) intumescent expandable graphite has a maximum free expansion of 150 to 500 ml / g, preferably 350 to 450 ml / g ,

According to a further preferred embodiment of a fire protection mixture according to the invention or of a fire protection article according to the invention, the intumescent expandable graphite preferably has a particle size in the range from 150 to 500 μm, particularly preferably in the range from 300 to 500 μm. Since the expandable graphite is usually screened to obtain the desired particle size, expandable graphite particles of smaller particle size are present in individual cases in addition to the expandable graphite particles of preferred particle size.

• ein maximal erzielbares Expansionsvolumen von 550 % / mg oder mehr,
• eine Expansionsgeschwindigkeit von 20 % / °C oder mehr im Bereich der Onset-Temperatur
• einen mittleren Ausdehnungskoeffizienten α zwischen Onset-Temperatur und T₁₀₀ von 0,1 K^-1 oder mehr.

In addition, an intumescent expandable graphite to be used according to the invention preferably has one, two or all of the following expansion parameters:

• a maximum achievable expansion volume of 550% / mg or more,
• an expansion rate of 20% / ° C or more in the onset temperature range
• a mean expansion coefficient α between onset temperature and T ₁₀₀ of 0.1 K ^-1 or more.

Expandable graphite types which can be used in the context of the present invention preferably have an onset temperature in a range from 140 to 180 ° C, preferably in a range from 140 to 160 ° C. Expanded graphites with intercalated sulfuric acid, as described above, usually have an onset temperature of about 200 ° C and are therefore less preferred for the purposes of the present invention and especially for an early or rapid foaming at low temperatures. Expanded graphites, however, based on so-called modified sulfuric acid as an intercalated reagent, are particularly preferred for the purposes of the present invention. For the purposes of the present text, modified sulfuric acid is understood as meaning, for example, sulfuric acid-containing mixtures which, in addition to the reagent to be intercalated (sulfuric acid), contain special admixtures (for example special oxidants) which are used in the production of intumescent expanded graphites for the expansion properties of the corresponding expandable graphite to influence. Alternatively, conventional expandable graphites can be modified with sulfuric acid as the intercalated reagent after intercalating the acid according to the desired expansion properties, particularly according to the desired onset temperature, for example, by washing the sulfuric acid-graphite particles with an aqueous washing liquid containing compounds containing the Modify expansion properties of expandable graphite (see for example DE 102 56 963 A1 ). Such modified expanded graphite or expandable graphite based on so-called modified sulfuric acid as an intercalated reagent, preferably have an onset temperature in the range of 140 to 180 ° C, more preferably in the range of 140 to 160 ° C, and are therefore for the purposes of Particular preference is given to using the present invention.

Alternatives to modified sulfuric acid as an intercalating reagent are acetic acid and nitric acid. The intercalation of acetic acid or nitric acid leads to expandable graphites with an onset temperature of about 150 to 160 ° C. However, these two acids lead to expansion parameters of the resulting expandable graphite, which do not meet the requirements of fast reaction systems in individual cases. The use of modified sulfuric acid is therefore particularly preferred.

The pH of the expandable graphite to be used is preferably neutral; Acid residues can possibly damage tools and / or plastics of the overall system.

For example, an expandable graphite type from Nordmann Rassmann (Nord-Min® 351) has proved particularly suitable for the purposes of the present invention. This expandable graphite type has an onset temperature of about 150 to 160 ° C. The parameters of this expandable graphite type are particularly suitable for the purposes of the present invention. In addition, it is advantageous that said preferred expandable graphite type has a graphite particle diameter (particle size) of about 300 μm. In addition, this expandable graphite type also has (modified) sulfuric acid as an intercalated reagent, as is also generally preferred in the context of the present invention. The purity of this graphite is more than 99%, the ash content is about 0.9%.

The (ii) (A) intumescent, alkane-filled microcapsules are to be understood in the context of the present text as microcapsules (microspheres), the one Outer shell made of a fusible material (preferably a plastic material) and inside a (preferably low-boiling) alkane as a propellant. In principle, depending on the application (eg fast-reacting or slower foaming), isobutane, n-butane, isopentane, n-pentane, isohexane or higher homologues can be used as the alkane.

Alternatively, the intumescent, alkane-filled microcapsules are within the scope of the present invention as described above preferably one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing blowing agent (eg Porofor ^®, Kenitron ^® and Ficel ^® from Lanxess; Azodicarboxamide as nitrogen abspaltendes Propellants, etc.) are used. The shell of this or this encapsulated blowing agent consists of a fusible material, preferably a plastic material.

Non-encapsulated blowing agents are inefficient for the purposes of the present invention, since upon heating the (gaseous) decomposition products of the blowing agents can escape through the porous structure of an inflating fire protection mixture or an intumescent fire protection article. By contrast, the microcapsules or encapsulated blowing agents to be used according to the invention allow a uniform, three-dimensionally directed foaming, without the gases being able to escape in advance. This will cause the material, i. a corresponding fire-protection mixture or a corresponding intumescent fire protection article, optimally distended.

The intumescent, alkane-filled microcapsules to be used according to the invention preferably have an outer shell of latex, polyvinylidene chloride, polyvinyl acetate or polyacrylic compounds. Particularly preferred are microcapsules whose plastic shell consists of a copolymer which is preferably based on the monomers vinylidene chloride, acrylonitrile and methyl methacrylate or constructed from these monomers (such as Expancel microcapsules from Akzo Nobel).

The diameter of intumescent, alkane-filled microcapsules to be used according to the invention is preferably from 6 to 45 μm, particularly preferably from 10 to 25 μm.

It is further preferred if the intumescent alkane-filled microcapsules to be used according to the invention have a solids content of 55 to 80%, preferably of 60 to 75%, preferably in an embodiment of the present invention designated above as preferred.

Intumescent, alkane-filled microcapsules or encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants which are to be used according to the invention have an onset temperature in a range from 75 to 170.degree. C., preferably in a range from 95 to 130.degree.

According to the preferred ingredients to be used above, another aspect of the present invention relates to a (a) fire-resistant mixture or a (b) intumescent fire-resistant article (each as defined above) wherein the onset temperature of the intumescent expanded graphite is in a range of 140 up to 180 ° C., preferably in a range from 140 to 160 ° C., and / or the onset temperature of the (ii) (A) intumescent, alkane-filled microcapsules or of (ii) (B) one or more encapsulated nitrogen oxides releasing and / or carbon dioxide-releasing propellant in a range of 75 to 170 ° C, preferably in a range of 95 to 130 ° C.

It is particularly preferred if the onset temperature of (i) intumescent expanded graphite in a range of 140 to 160 ° C and the onset temperature of the (ii) (A) intumescent, alkane-filled microcapsules or the (ii) (B ) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellant in a range of 95 to 130 ° C.

According to another aspect of the present invention, it is preferred that the onset temperatures of the intumescent, alkane-filled

Microcapsules or the one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellant and expandable graphite in an embodiment according to the invention by about 30 to 60 C, preferably about 40 ° C, apart, preferably in an embodiment referred to above as preferred of the present invention. The onset temperature of the (ii) (A) intumescent, alkane-filled microcapsules or the encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellant is preferably lower.

Accordingly, according to this aspect, a (a) fire protection mixture or a (b) intumescent fire protection article (as defined above) is specified, wherein the onset temperature of the (i) intumescent expanded graphite is higher by 30 to 60 ° C, preferably by 40 ° C is the onset temperature of the (ii) (A) intumescent alkane-filled microcapsules or (ii) (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants.

In the case of fire, the expansion process of the corresponding expandable graphite thus begins only after the beginning of the expansion of the intumescent, alkane-filled microcapsules or the encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants, so that the foaming effects can act synergistically.

In the event of a fire, the outer shell of the intumescent, alkane-filled microcapsules or the encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants softens, with simultaneous increase in internal pressure (due to evaporation of the propellant and thermal expansion of the gas). In the extreme case, preferably intumescent, alkane-filled microcapsules inflate up to forty times their original volume to a diameter of, for example, 240 to 1800 μm.

In such a three-dimensional increase in volume, the entire fire protection mass, d. H. the fire-protection mixture according to the invention or an intumescent fire-protection article according to the invention is greatly distended even at low temperatures, thereby allowing a fast-reacting foaming of the fire-protection mixture or of the fire protection article at a high speed, a high volume and a high pressure. The intumescent expanded graphite preferably to be used according to the invention reacts when the temperature continues to rise after reaching its corresponding onset temperature and thereby triggers a second expansion process in which a fire protection seal in the form of an intumescent layer is formed.

In this synergistic interaction, the graphite particles are, so to speak, "carried along" first by the expanding microcapsules or the encapsulated blowing agents and only puff themselves up during this process to form an intumescent layer. Thereby, an improvement of the expansion behavior of the overall system for the purposes of the present invention in the sense of the above-mentioned task (s) is achieved. The fire protection compound or the fire protection article is thus preferably "pre-expanded" by the action of intumescent, alkane-filled microcapsules or the encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellant, whereupon the intumescent expanded graphite the swollen, pre-expanded mass or the article with a surrounding protective intumescent layer.

On the other hand, a larger than the preferred difference between the onset temperatures separates the two blown processes from each other in terms of time, so that in the extreme case the two blown processes no longer overlap in time, which counteracts rapid expansion at a low onset temperature. The swollen microcapsules or encapsulated propellants can be decomposed by the heat of the fire before the corresponding expandable graphite begins to intumesce.

A combination of expanded graphite (as a primary intumescent material) and microspheres, or microcapsules containing isobutane, is associated with a two-stage swelling behavior in US 5,132,054 described. The purpose of the admixed microcapsules is a first expansion step at an onset temperature of about 99 ° C (210 ° F). This is followed by a second expansion step caused by the primary intumescent material upon reaching an onset temperature of about 163 ° C (325 ° F). Other than to optimize the expansion parameters, as in the present invention, the in US 5,132,054 but described the inflated microcapsules but the shape of the intumescent fire protection compound and a controlled foaming to prevent disintegration of the fire protection seal. The two onset temperatures are about 64 ° C apart.

The constituents of the fire-protection mixture according to the invention or an intumescent fire-protection article according to the invention therefore fulfill a different task within the scope of the present invention. In addition, the according to US 5,132,054 chosen difference of the two onset temperatures of the different intumescent constituents greater than one according to the invention to be preferred.

In a particularly preferred embodiment, the (ii) (A) intumescent, alkane-filled microcapsules which are contained in a fire-protection mixture according to the invention or an intumescent fire protection article according to the invention (as described above) are isopentane-filled microcapsules.

As already mentioned, different alkanes can be used depending on the application. The expansion parameters of the intumescent, alkane-filled microcapsules depend inter alia on the encapsulated alkane and the material of the outer shell. However, intumescent microcapsules containing isopentane as the corresponding propellant are particularly preferred for the purposes of the present invention. Preference is also given intumescent, isopentane-filled microcapsules having an onset temperature in the range of about 124 to 134 ° C. In accordance with the preconditions described above, such preferred microcapsules offer ideal properties for the purposes of the present invention.

Preferably, the (ii) (A) intumescent, alkane-filled microcapsules have their maximum expansion volume at a temperature in the range of 115 to 230 ° C, preferably in the range of 135 to 170 ° C (T ₁₀₀ ). In the extreme case, the volume of the microcapsules is increased by up to forty times the initial volume.

In our own studies have found that for example the so-called Expancel ^® microcapsules of type 551 DU 20, 551 DU 40, 461 DU 40, 051 DU 40, 053 DU 40, 091 DU 80, 920 DUX 40 and 009 DU 80 Company Akzo Nobel are particularly well suited for use for the purposes of the present invention. The type designations correspond to the status of 31.12.2007.

Although the (ii) (A) intumescent, alkane-filled microcapsules primarily fulfill another object in the context of the present invention, it was also possible to confirm for the intumescent, alkane-filled microcapsules to be used according to the invention that these are present in the abovementioned embodiments of a fire protection mixture according to the invention or an intumescent fire protection article according to the invention in case of fire to better shape and increased stability of the fire protection mixture or the fire protection article lead (see. US 5,132,054 ). In conventional fire protection mixtures without intumescent, alkane-filled microcapsules in the case of fire after inflation of the graphite particles and the associated partial decomposition of the graphite particles comprising matrix, the cohesion of the inflated fire protection mixture is often impaired, so that the first formed pipe closure or fire protection layer by thermal air currents or the like Effects can easily decay. By melting in case of fire By contrast, envelopes of the microcapsules form a binder, which holds the then inflating graphite particles together and in turn protects them from decomposition. The result is an intumescent layer with outstanding steadfastness in case of fire.

As already mentioned several times, component (iii) of a fire protection mixture according to the invention or an intumescent fire protection article of one or more flame retardants selected from the group consisting of: phosphate-containing flame retardants, halogen-containing flame retardants, mineral flame retardants, nitrogen-containing flame retardants, boron-containing flame retardants and phyllosilicates based on aluminum silicate clay minerals. The flame retardants mentioned inhibit or prevent in the event of a fire burning off of the components (i) to (iii) or (iv) comprising matrix material. Without appropriate flame retardants, the matrix material can ignite and burn off. As a result, there is a risk that the fire may migrate through the insulating or intumescent layer that forms due to the insufficiently protected matrix material, since combustible components (plastic) are contained in larger quantities. In addition, the source of the fire can be supplied with oxygen, as air can reach the matrix material due to the "leaky", expanded insulation layer. This can lead to the burning through of the insulating layer.

It is therefore provided according to the invention to provide the corresponding fire protection mixture or a corresponding intumescent fire protection article with one or more of the above-mentioned flame retardants.

1. a) phosphor- bzw. phospathaltigen Flammschutzmittel, insbesondere Phosphatester, Phosphate, Phosphonate, Phosphinate und Ammoniumpolyphosphate,
2. b) halogenhaltigen Flammschutzmittel, insbesondere bromhaltige Flammschutzmittel, insbesondere bromierte Phosphorsäureester, (cyclo)aliphatische Bromverbindungen (z.B. Hexabromcyclododecan (HBCD)) und aromatische Bromverbindungen (z.B. polybromierte Diphenylether (PBDEs), Tetrabrombisphenal A (TBBPA), bromierte Polystyrole, bromierte Phenole und Tretrabromphthalsäureanhydrid),
3. c) mineralischen Flammschutzmittel, insbesondere Aluminiumhydroxid (ATH) und Magnesiumhydroxid (MDH),
4. d) stickstoffhaltigen Flammschutzmittel, insbesondere Melamin, Melaninderivate (z.B. Melaminpolyphosphat und Melamincyanurat) und Melaminhomologe,
5. e) borhaltigen Flammschutzmittel, insbesondere Borax und Zinkborat,
6. f) Schichtsilikate auf Basis von Aluminiumsilikat-Tonmineralien, insbesondere Montmorillonit.

Preferably, the one or more flame retardants is selected from the group of

1. a) phosphorus- or phosphate-containing flame retardants, in particular phosphate esters, phosphates, phosphonates, phosphinates and ammonium polyphosphates,
2. b) halogen-containing flame retardants, in particular bromine-containing flame retardants, in particular brominated phosphoric esters, (cyclo) aliphatic bromine compounds (eg hexabromocyclododecane (HBCD)) and aromatic bromine compounds (eg polybrominated diphenyl ethers (PBDEs), tetrabromobisphenal A (TBBPA), brominated polystyrenes, brominated phenols and trietrabromophthalic anhydride) .
3. c) mineral flame retardants, in particular aluminum hydroxide (ATH) and magnesium hydroxide (MDH),
4. d) nitrogen-containing flame retardants, in particular melamine, melanin derivatives (eg melamine polyphosphate and melamine cyanurate) and melamine homologs,
5. e) boron-containing flame retardants, in particular borax and zinc borate,
6. f) phyllosilicates based on aluminum silicate clay minerals, in particular montmorillonite.

It has been found in our own investigations that the use of ammonium polyphosphate (s) is particularly advantageous for the purposes of the present invention. Ammonium polyphosphates, for example, have a higher efficiency compared to mineral flame retardants such as aluminum hydroxide or, in particular, montmorillonite and can therefore be used in smaller amounts. In addition, ammonium polyphosphates are themselves slightly intumescent and can thus support the swelling process. Ammonium polyphosphate is cleaved in case of fire in ammonia gas, which is intended to quench the flames, and in phosphoric acid, which forms a carbonaceous crust, which prevents the evaporation of combustible substances from the matrix material. In own attempts has itself For example, a flame retardant based on ammonium polyphosphates Thor Chemie GmbH (AFLAMMANN TL1017) proved to be particularly advantageous.

On the other hand, halogen-containing flame retardants are less preferred for environmental protection reasons.

The present invention according to another aspect relates to an intumescent fire protection article (as described above), preferably in an embodiment designated as preferred, wherein the fire protection article is a shaped article.

• (b1) eine Gesamtmenge von 10 bis 35 Gew.-%, vorzugsweise 20 bis 25 Gew.-%, (i) intumeszierenden Blähgraphits sowie 2 bis 20 Gew.-%, vorzugsweise 5 bis 10 Gew.-%, (ii) (A) intumeszierende, alkangefüllte Mikrokapseln,
  vorzugsweise 20 bis 25 Gew.-% (i) intumeszierenden Blähgraphits sowie 5 bis 10 Gew.-% (ii) (A) intumeszierende, alkangefüllte Mikrokapseln
  oder
• (b2) eine Gesamtmenge von 10 bis 35 Gew.-%, vorzugsweise 15 bis 25 Gew.-%, (i) intumeszierenden Blähgraphits sowie maximal 10 Gew.-%, vorzugsweise maximal 5 Gew.-%, (ii) (A) intumeszierende, alkangefüllte Mikrokapseln,
  vorzugsweise 15 bis 25 Gew.-% (i) intumeszierenden Blähgraphits sowie maximal 5 Gew.-% (ii) (A) intumeszierende, alkangefüllte Mikrokapseln,
  bezogen auf das Gesamtgewicht des intumeszierenden Brandschutzartikels.

According to a further preferred embodiment, an intumescent fire protection article according to the invention comprises

• (b1) a total amount of 10 to 35% by weight, preferably 20 to 25% by weight, of (i) intumescent expandable graphite and 2 to 20% by weight, preferably 5 to 10% by weight, (ii) A) intumescent, alkane-filled microcapsules,
  preferably from 20 to 25% by weight of (i) intumescent expanded graphite and from 5 to 10% by weight of (ii) (A) intumescent, alkane-filled microcapsules
  or
• (b2) a total amount of from 10 to 35% by weight, preferably 15 to 25% by weight, of (i) intumescent expanded graphite and not more than 10% by weight, preferably not more than 5% by weight, (ii) (A) intumescent, alkane-filled microcapsules,
  preferably 15 to 25% by weight of (i) intumescent expanded graphite and a maximum of 5% by weight of (ii) (A) intumescent, alkane-filled microcapsules,
  based on the total weight of the intumescent fire protection article.

Intumescent fire protection articles of these preferred embodiments are particularly advantageous for the purposes of the present invention mentioned above. Although amounts of intumescent, alkane-filled microcapsules above these preferred amounts can be used, they are generally too expensive, unnecessarily intensive foaming and, due to the increased proportion of additives, reduce the mechanical properties of the overall system.

An inventive intumescent fire protection article composed according to alternative (b1) has proved to be particularly advantageous, in particular for pipe bulkheading for combustible pipes. A composition according to alternative (b2) has surprisingly been found to be particularly advantageous for the purposes of Kabelabschottung.

Further preferred is an intumescent fire protection article (as described above), which according to alternative (b2) a total amount of 10 to 35 wt .-%, preferably 15 to 25 wt .-% (intumescent expanded graphite) and a maximum of 10 wt .-%, preferably at most 5% by weight, (ii) (A) intumescent, alkane-filled microcapsules,
such as
as another constituent (iv) a total amount of at most 10% by weight, preferably 2 to 5% by weight, of plastic powder
in each case based on the total weight of the intumescent fire protection article.

Preferably, the plastic powder is a PET powder, a PP powder or consists of low-melting PU materials or other low-melting plastics. On the other hand, plastic powders of infusible plastics (eg polyvinyl alcohol or polyacrylonitrile) or polymers that melt too high are not preferred.

In the case of fire, the plastic powder preferably to be used according to the invention fulfills an adhesive function in that it melts through the heat without decomposing prematurely and forms a viscous melt. The inflatable graphite particles of (i) intumescent expanded graphite in the case of fire protect the molten plastic of the plastic powder from being decomposed by high temperatures due to an insulating effect. The inflated graphite particles in turn are glued together by the viscous melt, resulting in a much more stable insulation or intumescent layer. Advantageously, a flame retardant used according to the invention protects such a plastic powder from (premature) burning off. In addition, since the melting point of such a plastic powder is preferably relatively low (e.g., AK-TPU: 135 ° C), it liquefies even at relatively low heat input before reaching the onset temperature of the expanded graphite. This ensures that an adhesion of the expanded graphite particles through the molten plastic powder occurs without this burns before.

According to another aspect of the present invention, there is provided an intumescent fire protection article according to an embodiment described above (with the exception of an intumescent fire protection article of the composition according to alternative (b2)), wherein the fire protection article is a pipe seal for combustible pipes or a component of such a pipe seal. Alternatively, such an intumescent fire protection article according to an embodiment described above (with the exception of an intumescent fire protection article of composition according to alternative (b1)) is a Kabelabschottung or a component of such Kabelabschottung.

A fire protection mixture according to the invention (as described above) is particularly suitable for the production of an intumescent fire protection article. Accordingly, a further aspect of the present invention relates to the use of a fire protection mixture according to the invention for producing an intumescent fire protection article, in particular one as above described intumescent fire protection article according to the invention. For the fire protection mixture or the fire protection article and its preferred embodiments, the above applies accordingly.

• Einbetten der Bestandteile (i), (ii), (iii) sowie gegebenenfalls (iv) sonstiger Bestandteile in ein Matrixmaterial.

The present invention moreover relates to a process for the preparation of a fire-protection mixture according to the invention for producing an intumescent fire protection article, in particular an intumescent fire protection article according to the invention described above. The method comprises the following step:

• Embedding ingredients (i), (ii), (iii) and optionally (iv) other ingredients in a matrix material.

For the preferred materials for the matrix material, but also the components (i), (ii), (iii) and optionally (iv), the above applies accordingly. Further embodiments will be apparent from the following embodiments below.

• zumindest teilweises Umschließen und/oder in Kontakt bringen eines Rohres oder eines oder mehrerer Kabel mit einer erfindungsgemäßen Brandschutzmischung (wie oben beschrieben) oder einem erfindungsgemäßen intumeszierenden Brandschutzartikel (wie oben beschrieben).

As already mentioned, a fire-protection mixture according to the invention or an intumescent fire protection article according to the invention is particularly well suited for the partitioning of combustible pipes or cables. Accordingly, the present invention also relates to a method for sealing combustible pipes or cables. This method according to the invention comprises the following step:

• at least partially enclosing and / or bringing into contact a pipe or one or more cables with a fire protection mixture according to the invention (as described above) or an intumescent fire protection article according to the invention (as described above).

The invention will be explained in more detail by means of exemplary embodiments.

Exemplary embodiment 1: Production of an intumescent fire protection article comprising 8% by weight Expancel microcapsules and 25% by weight expandable graphite 1) Preparation of the first component of a polymer matrix consisting of a two-component casting system based on polyurethane:

200.0 g of a Desmophen 3426L type polyol are degassed or dehydrated by applying a vacuum and simultaneously heating to 120.degree. Then allowed to cool to about 80 ° C and are 17.7 g of 1,4-butanediol and 11.3 g of trimethylolpropane as a crosslinking added. After complete dissolution of the trimethylolpropane, allow to cool to room temperature and add 0.4 g of Dabco MB20 and 1.8 g of Dabco NE1070 as catalysts. After the addition of these two catalysts are sequentially 14.2 g Baylith T ^® (as water adsorber), 127.6 g AFLAMMAN TL1017 (as the component (iii)), 56.6 g Expancel microcapsules (Type 920 DUX 40) (as component ( ii)) and 1.8 g of pigment. The constituents are mixed in and the air which is stirred in is removed again by subsequently applied vacuum. 177.4 g of NORD-MIN 351 expandable graphite (as constituent (i)) are then added with mechanical stirring and the air which is stirred in here is removed again by vacuum.

2) Production of the two-component casting system of the polymer matrix based on polyurethane for the production of a fire protection bandage (in particular for pipe penetration of combustible pipes):

For the production of a fire protection bandage as an intumescent fire protection article described under 1) manufactured first component of the two-component system with the second component, 100 g of a mixture of isomers of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the ratio 65:35 , thoroughly mixed and poured into shape. The material has a pot life in the range of about 5 to 10 minutes, depending on the ambient and mold temperature. After about 2 to 3 hours, the material can be removed from the mold.

With regard to the total weight of the fire protection bandage, this fire protection article comprises 8% by weight of Expancel microcapsules (as component (ii)) and 25% by weight of intumescent expanded graphite (as component (i)).

3) Comparative measurements:

In Schaumhöhemessungen at a temperature of 500 ° C has been shown that by adding 8 wt .-% Expancel microcapsules (according to the description under 1) and 2)) to a fire protection mixture for producing an intumescent fire protection article, the maximum foam height of the fire protection mixture or of the intumescent fire protection article can be increased by a factor of 1.5. Swelling pressure measurements at a temperature of 300 ° C resulted in a factor of 1.6 improvement over an identical control material without Expancel microcapsule additive.

The foam height was measured in accordance with the "Approvals Principles for Intumescent Building Materials" of DIBt (Deutsches Institut für Bautechnik).

Exemplary Embodiment 2 Production of an Intumescent Fire Protection Article Comprising 17% by Weight Expancel Microcapsules and 24% by Weight Expandable Graphite 1) Preparation of the first component of a polymer matrix consisting of a two-component casting system based on polyurethane:

200.0 g of a Desmophen 3426L type polyol are degassed or dehydrated by applying a vacuum and simultaneously heating to 120.degree. Then allowed to cool to about 80 ° C and are 17.7 g of 1,4-butanediol and 11.3 g of trimethylolpropane as a crosslinking added. After complete dissolution of the trimethylolpropane, allow to cool to room temperature and add 0.6 g of Dabco MB20 and 2.2 g of Dabco NE1070 as catalysts. After the addition of these two catalysts are sequentially 17.2 g Baylith T ^® (as water adsorber), 158.2 g AFLAMMAN TL1017 (as the component (iii)), 149.4 g Expancel microcapsules (Type 920 DUX 40) (as component ( ii)) and 2.2 g of pigment. The constituents are mixed in and the air which is stirred in is removed again by subsequently applied vacuum. 207.8 g of NORD-MIN 351 expandable graphite (as constituent (i)) are then added with mechanical stirring and the air which is stirred in here is removed again by vacuum.

2) Production of the two-component casting system of the polymer matrix based on polyurethane for the production of a fire protection bandage (in particular for pipe penetration of combustible pipes):

To produce a fire protection bandage as an intumescent fire protection article described under 1) manufactured first component of the two-component system with the second component, 100 g of a mixture of isomers of 4,4'-Dippenylmethandiisocyanat and 2,4'-diphenylmethane diisocyanate in the ratio 65:35 , thoroughly mixed and poured into shape. The material has a pot life in the range of about 5 to 10 minutes, depending on the ambient and mold temperature. After about 2 to 3 hours, the material can be removed from the mold.

With regard to the total weight of the fire protection bandage, this fire protection article comprises 17% by weight of Expancel microcapsules (as component (ii)) and 24% by weight of intumescent expanded graphite (as component (i)).

3) Comparative measurements:

In Schaumhöhemessungen at a temperature of 500 ° C has been shown that by adding 17 wt .-% Expancel microcapsules (according to the description under 1) and 2)) to a fire protection mixture for producing an intumescent fire protection article, the maximum foam height of the fire protection mixture or of the intumescent fire protection article can be increased by a factor of 2.4. Swelling pressure measurements at a temperature of 300 ° C resulted in a factor of 1.8 improvement over an identical control material without Expancel microcapsule additive.

The foam height was measured in accordance with the "Approvals Principles for Intumescent Building Materials" of DIBt (Deutsches Institut für Bautechnik).

Exemplary Embodiment 3 Production of an Intumescent Fire Protection Article Comprising 3% by Weight Expancel Microcapsules, 25% by Weight Expandable Graphite and 5% by Weight PET Powder 1) Preparation of the first component of a polymer matrix consisting of a two-component casting system based on polyurethane:

200.0 g of a Desmophen 3426L type polyol are degassed or dehydrated by applying a vacuum and simultaneously heating to 120.degree. Then allowed to cool to about 80 ° C and are 17.7 g of 1,4-butanediol and 11.3 g of trimethylolpropane as a crosslinking added. After complete dissolution of the trimethylolpropane, allow to cool to room temperature and add 0.4 g of Dabco MB20 and 1.8 g of Dabco NE1070 as catalysts. After the addition of these two catalysts are sequentially 14.2 g Baylith T ^® (as water adsorber), 127.6 g AFLAMMAN TL1017 (as the component (iii)), 21.2 g Expancel microcapsules (Type 920 DUX 40) (as component ( ii)), 35.4 g of PET powder (≤ 250 μm) and 1.8 g of pigment. The constituents are mixed in and the air which is stirred in is removed again by subsequently applied vacuum. 177.4 g of NORD-MIN 351 expandable graphite (as constituent (i)) are then added with mechanical stirring and the air which is stirred in here is removed again by vacuum.

2) Production of the two-component casting system of the polymer matrix based on polyurethane for the production of a fire protection bandage (in particular for cable insulation):

For the production of a fire protection bandage as an intumescent fire protection article described under 1) manufactured first component of the two-component system with the second component, 100 g of a mixture of isomers of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the ratio 65:35 thoroughly mixed and poured into shape. The material has a pot life in the range of about 5 to 10 Minutes, depending on the ambient and tool temperature. After about two to three hours, the material can be removed from the mold.

Claims (13)

(A) fire protection mixture for producing an intumescent fire protection article, comprising
or (b) intumescent fire protection article comprising
a matrix material in which the following components are embedded: (i) intumescent expanded graphite, (Ii) (A) intumescent, alkane-filled microcapsules,
or (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants, such as (Iii) one or more flame retardants selected from the group consisting of: phosphate-containing flame retardants, halogen-containing flame retardants, mineral flame retardants, nitrogen-containing flame retardants, boron-containing flame retardants and phyllosilicates based on aluminum silicate clay minerals; and
possibly (iv) other ingredients. (a) Fire protection mixture or (b) intumescent fire protection article according to claim 1, wherein component (ii) consists of intumescent, alkane-filled microcapsules. (A) fire protection mixture or (b) intumescent fire protection article according to claim 1 or 2, wherein the (i) intumescent expandable graphite has a maximum free expansion of 150 to 500 ml / g, preferably from 350 to 450 ml / g. (A) fire protection mixture or (b) intumescent fire protection article according to claim 1, 2 or 3 wherein the onset temperature of the intumescent expanded graphite is in a range from 140 to 180 ° C, preferably in a range from 140 to 160 ° C,
and or the onset temperature of the (ii) (A) intumescent, alkane-filled microcapsules or of (ii) (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants in a range from 75 to 170 ° C, preferably in a range of 95 to 130 ° C, is located. (A) fire-protection mixture or (b) intumescent fire protection article according to any one of claims 1 to 4, wherein the onset temperature of (i) intumescent expanded graphite by 30 to 60 ° C, preferably by 40 ° C, higher than the onset temperature the (ii) (A) intumescent, alkane-filled microcapsules or of (ii) (B) one or more encapsulated nitrogen-releasing and / or carbon dioxide-releasing propellants. (a) Fire protection mixture or (b) intumescent fire protection article according to any one of claims 2 to 5, wherein the (ii) (A) intumescent, alkane-filled microcapsules are intumescent, isopentane-filled microcapsules. An intumescent fire protection article according to any one of the preceding claims, wherein the fire protection article is a molded article. Intumescent fire protection article according to one of claims 2 to 7,
full (b1) a total amount of 10 to 35% by weight, preferably 20 to 25% by weight, of (i) intumescent expandable graphite and 2 to 20% by weight, preferably 5 to 10% by weight, (ii) A) intumescent, alkane-filled microcapsules,
preferably from 20 to 25% by weight of (i) intumescent expanded graphite and from 5 to 10% by weight of (ii) (A) intumescent, alkane-filled microcapsules
or (b2) a total amount of from 10 to 35% by weight, preferably 15 to 25% by weight, of (i) intumescent expanded graphite and not more than 10% by weight, preferably not more than 5% by weight, (ii) (A) intumescent, alkane-filled microcapsules,
preferably 15 to 25% by weight of (i) intumescent expanded graphite and a maximum of 5% by weight of (ii) (A) intumescent, alkane-filled microcapsules,
based on the total weight of the intumescent fire protection article. An intumescent fire protection article according to claim 8 comprising
according to alternative (b2) a total amount of 10 to 35 wt .-%, preferably 15 to 25 wt.% (i) intumescent expanded graphite and at most 10 wt .-%, preferably at most 5 wt .-%, (ii) (A) intumescent, alkane-filled microcapsules,
such as
as a further constituent (iv) a total amount of not more than 10% by weight, preferably from 2 to 5% by weight, of plastic powder,
in each case based on the total weight of the intumescent fire protection article. Intumescent fire protection article - one of claims 1 to 7 or claim 8, alternative (b1), wherein the fire protection article is a pipe bulkhead for combustible pipes or a part of such a Rohrabschottung, or - One of claims 1 to 7 or to claim 8, alternative (b2), or claim 8, wherein the fire protection article is a Kabelabschottung or a part of such Kabelabschottung. Use of a (a) fire-protection mixture according to one of claims 1 to 6 for the production of an intumescent fire-protection article, in particular of a (b) intumescent fire-protection article according to one of claims 1 to 10. Process for producing a (a) fire-protection mixture according to one of Claims 1 to 6 for producing an intumescent fire-protection article, in particular a (b) intumescent fire-protection article according to one of Claims 1 to 10, with the following step: - Embedding the ingredients (i), (ii), (iii) and optionally (iv) other ingredients in a matrix material. Method for sealing flammable pipes or cables, comprising the following step: at least partially enclosing and / or bringing into contact a pipe or one or more cables with a (a) fire protection mixture according to one of claims 1 to 6 or a (b) intumescent fire protection article according to one of claims 1 to 10.